Status asthmaticus: a large MICU experience

Management of critical asthma syndrome during pregnancy

One-third of pregnant asthmatics experience a worsening of their asthma that may progress to a critical asthma syndrome (CAS) that includes status asthmaticus (SA) and near-fatal asthma (NFA). Patients with severe asthma before pregnancy may experience more exacerbations, especially during late pregnancy. Prevention of the CAS includes excellent asthma control involving targeted early and regular medical care of the pregnant asthmatic, together with medication compliance. Spontaneous abortion risk is higher in pregnant women with uncontrolled asthma than in non-asthmatics. Should CAS occur during pregnancy, aggressive bronchodilator therapy, montelukast, and systemic corticosteroids can be used in the context of respiratory monitoring, preferably in an Intensive Care Unit (ICU). Systemic epinephrine should be avoided due to potential teratogenic side-effects and placental/uterine vasoconstriction. Non-invasive ventilation has been used in some cases. Intratracheal intubation can be hazardous and rapid-sequence intubation by an experienced physician is recommended. Mechanical ventilation parameters are adjusted based on changes to respiratory mechanics in the pregnant patient. An inhaled helium-oxygen gas admixture may promote laminar airflow and improve gas exchange. Permissive hypercapnea is controversial, but may be unavoidable. Sedation with propofol which itself has bronchodilating properties is preferred to benzodiazepines. Case reports delineating good outcomes for both mother and fetus despite intubation for SA suggest that multidisciplinary ICU care of the pregnant asthmatic with critical asthma are feasible especially if hypoxemia is avoided.

Management of the obstetric patient with status asthmaticus

Status asthmaticus requiring mechanical ventilation is an uncommon, life-threatening disorder in obstetric patients. The unique physiologic changes of pregnancy, impact of the fetus on the maternal condition, and concerns for fetal and maternal health and survival are particular concerns in critical illness. Furthermore, the issues of hypoxemia and hypercapnia, ventilator management and complications make this disease of respiratory failure an especially important area for review. There is abundant literature on the management of asthma during pregnancy; however the literature is very limited in those with status asthmaticus who require intensive care unit admission. We report our intensive care unit experience in the management of status asthmaticus in 5 pregnant patients and review the literature on management of status asthmaticus during pregnancy.

Critical care of the obstetric patient

The obstetric patient poses exceptional challenges in the intensive care unit. Knowledge of the physiologic changes of pregnancy and specific pregnancy-related disorders is necessary for optimal management. Intensive care unit diagnoses may include preeclampsia, including the HELLP syndrome, pulmonary embolic disease, amniotic fluid embolism, status asthmaticus, respiratory infection, the acute respiratory distress syndrome, and sepsis. The management of mechanical ventilation is based on principles of avoiding lung injury, and hypercapnia may be tolerated even during the pregnancy. When the clinician is faced with the extraordinary instance of cardiopulmonary arrest, perimortem cesarean delivery must be considered to improve the potential for maternal and fetal survival.